<!DOCTYPE html> <html> <head> <style type="text/css"> #a { width: 15em; border: 1px solid black; } #b { float: right; width: 8em; height: 3em; background: #ccc; } </style> </head> <body> <div id="a"> <div id="b">float right</div> <div>Long text long text long text long text long text long text long text long text long text long text long text long text long text</div> </div> <script> var longWord = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"; document.body.offsetWidth; n = document.getElementById("b").nextSibling; n.data = longWord + n.data; </script> </body> </html>